Abstract

We demonstrate the possibility of enhancing both the magnetocaloric effect (MCE) and refrigerant capacity (RC) in nanostructured mixed phase manganites. A comparative study of the magnetic and magnetocaloric properties of in single crystalline and nanocrystalline forms is presented. While the conventional trend is reduction of magnetization and MCE with nanostructuring, we show that the opposite is true in the case of mixed phase manganites. The charge-ordered state is largely suppressed and ferromagnetic order is established in the nanocrystalline sample with an average particle size of 50 nm. Consequently, a strong enhancement of MCE and RC and a strong reduction of thermal and field hysteresis losses are achieved in the nanocrystalline sample. This finding opens up a way of exploring magnetic refrigerant materials at the nanometer scale for active magnetic refrigerators.

Received 23 July 2010Accepted 22 November 2010Published online 13 December 2010

Acknowledgments:

Work at USF was supported by DOE BES Physical Behavior of Materials Program through Grant No. DE-FG02-07ER46438. Work at Rutgers was supported by Grant No. DE-FG02-07ER46382. Work at HUT was supported by NAFOSTED through Grant No. 104.02.74.09.